Arsene Wenger admitted he could understand why Sol Campbell left Highbury at half-time after being substituted during the 3-2 home defeat by West Ham.

England centre-back Campbell, 31, was at fault for the opening goal as his slip allowed Hammers skipper Nigel Reo-Coker to dash through and put the visitors into the lead on 25 minutes.

Things got worse when the defender's slip allowed Bobby Zamora space to turn in the area, the former Tottenham striker sending a looping shot over Jens Lehmann.

Although Thierry Henry pulled a goal back his 151st league strike, bettering Cliff Bastin's record - before half-time, there was to be no comeback for the hosts, who missed the chance to move within a point of fourth-placed Spurs.

Matthew Etherington's strike with nine minutes left proved decisive, even though Robert Pires' late effort threatened to set up a grandstand finish.

"He was very down at half-time and he felt guilty," Wenger said of Campbell.

"We wanted to fight for him in the second half. It was not a disaster 2-1 down. I took him off because he was in a mental shape, I felt too much down to come back."

The Arsenal manager also revealed Campbell had taken the decision to leave the stadium himself.

"At half-time I had other worries, I decided to change Sol and then you go on with it," said Wenger. "I knew it would be better for him personally, I felt.

"You always want your players to stay, but there are exceptional circumstances where you can understand what he did tonight.

"He did not do it meaning disrespect to the club or to the team, but I feel he's very, very down and that's the only issue tonight. His confidence is not at the highest at the moment."

Wenger added: "It was a gamble because I had no defenders on the bench. At the moment we are of course short because we lost Lauren for the rest of the season and Ashley Cole is not back, Kolo [Toure] and [Emmanuel] Eboue are away, Sol is not well."